Part I of this book is dedicated to the proceedings of symposium I of the EMRS 1996 Spring Meeting. This Symposium on "New Trends in Ion Beam Processing of Materials" was held in Strasbourg (France) from the 4th to the 7th of June 1996. Ion- beam processing represents a particularly powerful tool to modify and synthesise materials such as semiconductors, metals, dielectrics, and ceramics, In particular, the continuous development of the semiconductor industry, with the consequent shrinkage of device dimensions, is placing severe constraints on ion-beam processing with demands for keV and meV energy beams, high doses, and unprecedented control over contamination, beam purity, and divergence. These requirements are posing new challenges to the ion-beam community, ranging from fundamental processes (such as defect generation, defect-defect interactions, phase transitions) to engineering (such as process control and novel equipment). The aim of this Symposium was to provide an international forum for the presentation and discussion of new work in the field of ion-beam processing. More than a hundred papers were presented by scientists from all over the world. particular emphasis was given to new trends in ion-beam processing of semiconductors and to the current challenges faced by microelectronic device manufacturing. The fields of transient- enhanced diffusion, gettering, optoelectronic applications, group IV hetero epitaxy, damage, annealing, and synthesis were treated in detail. The interaction between the semiconductor and other communities is important for the development of new concepts and presentations in the field of metals, insulators, and new techniques (such as plasma-immersion ion implantation) were extremely interesting. Part II is dedicated to the proceedings of symposium K. This symposium has focused on modifications of the structure and properties of materials which are induced by several kinds of irradiations: on the one hand high energy deposited in the electrons which relax their energy to the lattice (fs lasers, heavy ions in the GeV energy range, cluster beams in the MeV range) and on the other hand energy deposited directly on the lattice atoms (heavy ions and cluster beams in the keV energy range). The idea was to emphasize the link between the material modifications on a nanometric scale and the energy input on the fs time scale from both the experimental and theoretical point of view. To reach these goals our attention was focused on single event effects: single fs laser shots, single ion and cluster tracks (low and high energy).